Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)

Bukhari :: Book 5 :: Volume 59 :: Hadith 575

Narrated Ibn Abbas:

Allah's Apostle set out towards Hunain in the month of Ramadan
and some of the people were fasting while some others were not
fasting, and when the Prophet mounted his she-camel, he asked for a
tumbler of milk or water and put it on the palm of his hand or on
his she-camel and then the people looked at him; and those who were
not fasting told those who were fasting, to break their fast (i.e.
as the Prophet had done so). Ibn Abbas added, "The Prophet went (to
Hunain) in the year of the Conquest (of Mecca)."